Blow molded drum

ABSTRACT

Steel and plastic drums are utilized in many industries for transporting and storing various liquids which may be utilized as fuels, lubricants, ingredients, process fluids, or the like. Often the liquids transported and stored in such drums are highly caustic and/or hazardous and absolute containment during storage, transport, and handling are essential. For example in the semiconductor industry, caustic chemicals such as hydrofluoric acid are commonplace. Some liquids develop significant internal gas pressures when contained during storage. Such pressures must be periodically vented. Even when drums with such hazardous and caustic liquids are on site and ready for use, great care must be taken in accessing the liquids so as not to expose personnel or the environment to such chemicals.

[0001] This application is a continuing application of U.S. applicationSer. No. 09/541,871, filed Apr. 3, 2000, which is a continuation-in-partof U.S. application Ser. No. 08/982,671, filed Dec. 2, 1997, now issuingas U.S. Pat. No. 6,045,000 issued Apr. 4, 2000. Said applications andpatent are hereby incorporated by reference in their entirety.

BACKGROUND OF THE INVENTION

[0002] This invention relates to drums or barrels. More particularly itrelates to plastic drums with drum inserts for accessing the fluid inthe drum and closures for same.

[0003] Steel and plastic drums are utilized in many industries fortransporting and storing various liquids which may be utilized as fuels,lubricants, ingredients, process fluids, or the like. Often the liquidstransported and stored in such drums are highly caustic and/or hazardousand absolute containment during storage, transport, and handing areessential. For example in the semiconductor industry, caustic chemicalssuch as hydrofluoric acid are commonplace. Some liquids developsignificant internal gas pressures when contained during storage. Suchpressures must be periodically vented. Even when drums with suchhazardous and caustic liquids are on site and ready for use, great caremust be taken in accessing the liquids so as not to expose personnel orthe environment to such chemicals.

[0004] Plastic drums utilized in the semiconductor processing industrytypically have standardized openings on the top of the drums. Theseopenings comprise a pair of ports or bungholes, each having a fittingwith a neck extending upward from the top wall of the drum approximately1 to 1½ inches. The ports each have 2-inch internal buttress threads.Several closures or bungs may be utilized with these standardized portsincluding standard bung closures which are threadedly inserted into theopenings and which engage with the top shoulder of the neck. Thesestandard bung closures extend a fraction of an inch above the neck.

[0005] Access to the liquids in the plastic drums is typicallyaccomplished by multiple port bung connectors which attach to druminserts such as disclosed in U.S. Pat. No. 4,699,298, issued to Grant,et al, and assigned to FSI International Corporation and as disclosed inU.S. Pat. No. 5,108,015, issued to Rauworth, the inventor in the instantapplication with the same assignee, Fluoroware, Inc. These patents arehereby incorporated by reference. The bung connectors illustrated inthese patents have drum inserts with down hole tubes extending to theinside bottom of the drums for withdrawing the liquid in the drum andfor providing a means for sensing the level of the liquid in the drum.An additional tube or port in the insert is utilized for supplying airor other gas to replace the liquid as it is withdrawn. The drum insertis threadably engaged to one of the ports at the buttress threads inplace of and in the same fashion as a standard bung closure. The druminsert has external threads to engage the multiple port bung connectorhead which will have lines to the processing equipment or other storagecontainers.

[0006] The drum inserts, as disclosed in Grant and Rauworth patentsextend above the shoulder of the neck of the drum port into which theyare installed approximately ⅜ to ½ of an inch. Closures for the druminserts to be used when the multiple port bung connector head is not inplace are configured in several different ways. For example the closureof FIG. 5 includes a vent connection port and a valve for ventinginternal drum pressure. Each configuration of closures add an inch to aninch and ¼.

[0007] To aid in handing steel and plastic drums, protruding annularlips, commonly termed “chimes”, will typically be an integral part of oran attached part of the drums. The chimes extend upwardly at the top anddownwardly at the bottom of the drums. The chimes provide a grasping lipwhich is gripped by mechanized handling equipment equipped with a“parrot beak”.

[0008] Drums may be stacked either with pallets or other spacersintermediate vertically adjacent drums or the drums may simply bestacked on top of one another. The chime at the top of the drum alsoprovides protection to the top ports and connectors, particularly whenthe drums are stacked. The top of the chime needs to extend above theports and connectors to provide this protection. Known existing drumswith integral chimes extend at most, only a fraction of an inch abovethe shoulder of each neck at the drum ports. Although plastic compositedrums are known which utilize a separate chime portion attached to thetop of the drum and which are positioned high enough off the top of thedrum such that the various known closures do not extend thereabove, theprior art does not disclose such a drum with an integral top structure.

SUMMARY OF THE INVENTION

[0009] A plastic blow molded drum has unique top and bottom structureproviding protection and strength for the drum and attachments. Anintegrally formed top structure with a sufficiently deep recess providesprotection for drum inserts and associated closures. Additionally, thebottom structure includes a sump and structural member formed by thepinched-off parisan during the blow molding process. The drum has a topwall, a cylindrical side wall, and a bottom wall defining an openinterior. The top wall has an access port comprising a fittingintegrally formed with the drum. The fitting having an upwardlyextending neck with inside threads and a top shoulder. A drum insert isengaged with the fitting and provides an additional second threadedfitting and a second shoulder both extending upwardly above the shoulderof the integral fitting. A closure comprising a plug portion and athreaded nut portion engages the second threaded fitting, closes theport, and extends above the second shoulder. The closure has anuppermost portion, which may be a protective cover or venting valvehandle. The protective recess may suitably be formed by the chime and/orfurther downward recessed portions of the top wall such that the firstfitting, the second fitting, and the closure, including the uppermostportion of the closure are all below the top edge of the chime.

[0010] The bottom structure has a lower chime, a sump directly below theaccess port, and channels extending into the sump. A structural memberformed of the parisan pinch off material extends in a diametricdirection across the mid-portion of the bottom wall.

BRIEF DESCRIPTION OF THE DRAWINGS

[0011]FIG. 1 is perspective view of the combination of a drum, druminsert, and closure.

[0012]FIG. 2 is a detailed cross-sectional view of the top structure ofa drum at a bunghole with a drum insert and closure in place.

[0013]FIG. 3 is an exploded cross-sectional elevational view of a druminsert and closure known in the art.

[0014]FIG. 4 is a perspective view of a closure known in the art.

[0015]FIG. 5 is a exploded perspective view of a venting bung closureknown in the art.

[0016]FIG. 6 is an elevational view of the closure of FIG. 5 known inthe art.

[0017]FIG. 7 is a cross-sectional view of a drum according to theinvention.

[0018]FIG. 8 is a cross-sectional view of the top structure of a drumaccording to the invention and illustrating relative dimensions.

[0019]FIG. 9 is a cross-sectional view of the top structure of a drumaccording to the invention and illustrating relative dimensions.

[0020]FIGS. 10 and 11 are detail views of the bottom structure of thedrum according to the invention.

DETAILED SPECIFICATION

[0021] Referring to FIGS. 1 and 2, the invention is generally designatedwith the numeral 20. FIG. 1 shows in perspective a plastic blow moldeddrum 24 comprised of a cylindrical wall portion 26, a top structure 30and a bottom structure 34. The top structure is comprised of an upwardlyextending chime 40, a top wall 44 including a recessed portion 46, andan upwardly extending first fitting 50. FIG. 2 shows a portion of thedrum and added components forming the inventive combination.

[0022] Attached and inserted into the first fitting is a drum insert 54which includes a tube 56 which extends downwardly to the bottom 58.Threadably secured to the drum insert 54 is the closure 60 which plugsthe drum insert 54. Shown displaced from the drum, is a multiple portbung connector 59 which also fits on the drum insert 54 in place of theclosure when the liquid in the drum is to be withdrawn. Significantly,the closure as well as the drum insert are positioned below the top edge64 of the chime 40. The top structure has a first bunghole 36 and asecond bunghole 38. As shown in FIG. 1, a second bunghole utilizes astandard bung 65 which sealingly and threadably engages with the secondbung hole 38. Referring to FIG. 2, a detailed cross-sectional view ofthe top structure and the first bunghole is shown. The first fitting 50has a first neck portion 68 and a first shoulder 70. On the inside ofthe neck portion are two inch buttress threads 72 which have becomestandard in the industry. The first fitting 50 extends upwardly from therecessed portion 46 of the top wall 44.

[0023] Referring to FIGS. 2 and 3, engaged with the threaded portion 74is the drum insert 54. The drum insert has a base portion 78 whichincludes threads 80 which engage with the buttress threads 72 of thefirst neck portion 68. The drum insert includes a seating portion 84,which engages and seats on the first shoulder 70, a second fitting 85with a second threaded neck portion 86, a second shoulder portion 87,and fluid flow openings 89.

[0024] Closing the drum insert is the bung or closure 60 which iscomprised of a nut portion 88, configured as a handle, and a plugportion 90. The plug portion 90 may be comprised of two componentsjoined together, a sealing member 92 and a retaining member 94. Thehandle 88 freely rotates with respect to the plug portion 90.

[0025] The drum insert also has a down hole tube portion 55 and suctiontube 56 for withdrawing the liquid and a level sensing tube 98, bothextending from the base portion 78.

[0026] An alternative closure is shown in FIGS. 5 and 6. This ventingclosure 100 has a nut portion 88, configured as a handle, a plug portion90, both similar to these components in the closure of FIGS. 2 and 3.Additionally the venting closure 100, has a valve 104, a valve handle110, and a vent port or outlet 106. A cover 108 engages and fits overthe valve handle 110 and may be secured in place by way of a cap 112which engages on and seals the outlet 106. The closures of FIGS. 3 and 5are known in the art and are available from Fluoroware, Inc., theassignee of this application.

[0027] Referring to FIG. 2, the dashed lines with the numeral 116indicate the relative positioning of the venting closure with the cover108 and cap 112 in place. The top structure including the chime 40 andtop wall 44 are configured such that even with this relatively “high”closure, the top edge 64 of the chime is still the uppermost part of thecombination.

[0028] Referring to FIG. 7, a detailed cross-sectional view of the drumwithout attached drum inserts or closures is shown. In this embodimentthe fittings 50, 51 extend upwardly from a slightly recessed portion 46of the top wall 44. The mid-portion 116 of the top wall is shown asbeing slightly thickened relative to the recessed portion 46. Thisallows the fittings to drain adequately when the drum 24 is tippedupside down.

[0029] Referring to FIGS. 8 and 9, the relative size and positioning ofpertinent features of the top structure are illustrated. The recessportion 46 of the top wall 44 can be localized at the bunghole 36, FIG.8, or can extend to substantially all of, including all of the top wall,FIG. 9. The bunghole 36 will typically be the standard two-inch opening.The first fitting will extend a distance d1 of approximately 1 to 1¼inches above the top surface 118 of the recessed portion 46 of the topwall 44. The drum insert 54 will typically extend a distance d2 of 1 to1½ inches above the shoulder 70 or the uppermost surface 71 of the firstfitting 50. The closures 60 will typically extend a distance d3 of ⅜ to1 inch. The required height h1 of the chime above the top surface 118can vary depending on the configuration of the top wall 44. If therecess portion 46 is localized at the bunghole as shown in FIG. 8, theheight h1 can range from 1½ inches to 2¼ inches. Where the recessportion extends throughout the topwall 44, the height h2 will typicallybe 2¼ to 2¾ inches in height to accommodate the fitting 50, the druminsert 54, and the closure 60. The buttress thread length 11 in the neckportion 68 of the first fitting 50 is approximately ½ to ¾ of an inch.The length 12 of the threads on the second fitting 86 is approximately ½inch. The height h4 of the first fitting 68, the portion of the druminsert above the fitting 68, and the closure 60, assembled together, isapproximately 2¼ to 2¾ inches. The height h3 of the combined portion 119of the drum insert and closure above the fitting 68, is approximately 1¼inches for typical components.

[0030] The distance d1 is approximately half or less than half of thedistance h2 from the recessed portion to the top 64 of the chime. Theheight h3 is also approximately half or less than half of the distanceh2 from recessed portion to the top 64 of the chime. And significantly,the height h4, which is the sum of d1 and h3, is less than the heighth2.

[0031] The entire top structure 30 of the drum 24 is integrally formedby way of blow molding. An example of methodology for forming integralchimes during blow molding is disclosed in the prior art; for example,U.S. Pat. No. 4,228,122 to Theo Hammes and assigned to Mauser-KommanditGesellschaft, which is hereby incorporated by reference.

[0032] Referring to FIGS. 7, 10, and 11, details of the bottom structure34 of the drum are shown. A lower chime 122 extends downwardly from andis an integral part of the cylindrical side wall 26. Also integral is abottom wall 126 which includes a sump 130 and a channel 132 including araised channel portion 136 and inclined channel portions 138 and 140which slope downwardly from the raised portion 136 to the sump 130. Theraised portion 136 and the inclined portions 138, 140 may have theoutside surface 144 of said features positioned to be slightly raisedfrom a horizontal surface on which the drum may sit when the drum isempty or partially empty. Said spacing and thickness of the lower bottomwall may be configured such that as the barrel approaches apredetermined fill point, said channels are deflected downwardly by theweight of the liquid to contact and sit on the horizontal surface 150defining a resting plane 151. Then as the barrel is emptied, saidfeatures can be raised off of the horizontal surface to allow completedrainage of the channel. Such a resilient raised portion allows maximumcapacity of the drum while still facilitating stability and totaldrainage of the interior 160 of the drum.

[0033] During the blow molding process, the parisan is pinched off as isdisclosed in U.S. Pat. No. 4,946,368 to Masumoto and assigned to MitsuiPetro-Chemical Industries, Ltd. Said patent is hereby incorporated byreference. The pinched off parisan 166 is pinched off at the lowersurface 168 rather than at a location adjacent to the bottom wall. Thisadditional member 166 can provide additional stability for the drum whenplaced on a horizontal surface and can further facilitate the drainagefunction by maintaining and controlling the height of the midportion 170of the bottom wall, particularly with respect to the channels 132.Additionally the member 166 can facilitate movement of the barrel whenin the upright position on roller conveyors.

[0034] As with the top structure, all of the components and features asshown in FIGS. 7, 10 and 11 are integrally formed during the blowmolding process.

[0035] The present invention may be embodied in other specific formswithout departing from the spirit or essential attributes thereof, andit is therefore desired that the present embodiment be considered in allrespects as illustrative and not restrictive, reference being made tothe appended claims rather than to the foregoing description to indicatethe scope of the invention.

1. A combination plastic molded drum, and closure, the plastic moldeddrum comprising a cylindrical wall, a top structure, and a bottomstructure: the top structure, the cylindrical wall, and the bottomstructure all integrally molded; the top structure comprising a top walland a chime having a top edge extending circumferentially around,upwardly, and radially outward with respect to said top wall, the topwall comprising an integrally molded recessed portion, the top structurefurther comprising an upwardly extending first fitting integrally moldedwith the recessed portion and extending therefrom, the first fittinghaving a first neck portion, wherein the distance from the recessedportion to the top of the first fitting is about 1 to 14 inches andwherein the distance from the recess portion to the top of the top edgeof the chime is 1½ to 2¼ inches, the recessed portion positioned suchthat the first fitting, and the closure do not extend above the top edgeof the chime.
 2. The combination of claim 1 wherein the recessed portionis localized around the first fitting.
 3. The combination of claim 1wherein the recessed portion extends substantially throughout the topwall.
 4. The combination of claim 1 wherein the closure comprises a ventoutlet and a vent valve for relieving pressure within the drum.
 5. Thecombination of claim 4 further comprising a cover extending over thehandle, the vent outlet, and vent valve.
 6. A combination blow moldedplastic drum, and closure, the plastic molded drum comprising, acylindrical wall, a top structure, and a bottom structure, the topstructure and the cylindrical wall integrally molded; the top structurecomprising a top wall, an integral recessed portion, an upwardlyextending first fitting extending from the recessed portion, and anupwardly extending chime; the top wall, the recessed portion, the firstfitting, and the chime all integrally molded; the closure engageablewith the second fitting to secure the closure in place on the drum; thechime extending above the closure when the closure is secured on thedrum insert, the chime extending about the recessed portion 1½ to 2¾inches.
 7. The combination of claim 6, wherein the recessed portion islocalized around the first fitting.
 8. The combination of claim 6,wherein the recessed portion extends substantially throughout the topwall.
 9. The combination of claim 6, wherein the closure comprises avent outlet and a vent valve for relieving pressure within the drum. 10.The combination of claim 6, wherein the first fitting extends from therecessed portion a distance not more than substantially one half thevertical distance between the recessed portion and the top edge of theupperwardly extending chime.
 11. A combination blow molded plastic drum,and closure, the plastic molded drum comprising, a cylindrical wall, atop structure, and a bottom structure, the top structure and thecylindrical wall integrally molded; the top structure comprising a topwall, an integral recessed portion, an upwardly extending first fitting,and an upwardly extending chime; the top wall, the recessed portion, thefirst fitting, and the chime all integrally molded; the closureengageable with the second fitting to secure the closure in place on thedrum, the chime extending above the closure when the closure is securedon the drum insert, the height of the chime sufficient to allow aclosure to extend 1¼ inches above the top of the fitting and be belowthe top edge of the chime.
 12. The combination of claim 11, wherein therecessed portion is localized around the first fitting.
 13. Thecombination of claim 11, wherein the recessed portion extendssubstantially throughout the top wall.
 14. The combination of claim 11,wherein the closure comprises a vent outlet and a vent valve forrelieving pressure within the drum.
 15. The combination of claim 11,wherein the first fitting extends from the recessed portion a distancenot more than substantially one half the vertical distance between therecessed portion and the top edge of the upperwardly extending chime.